Slotting, perforating, and splining of tubes and the like



Feb. 16, 1937. E. G. BOYER 2,070,780

7 SLOTTING, PERFORATING, AND SPLINING OF TUBES AND THE LIKE Filed Feb. 28, i955 INVIENTOR kgzls-iaw/ ATTORNEY I Patented Feb. 16, 1937 UNITED STATES PATNT OFFIQE SLOTTING, PERFORATING, AND SPLINING OF TUBES AND THE LIKE corporation of Illinois Application February 28, 1935, Serial No. 8,705

5 Claims.

This invention relates to slotting, perforating or splining, and particularly to outwardly tapering slots, perforations or splines in pipes, tubes, and the like. Among other objects, the invention aims to provide an improved type of slot or spline efficiently and at relatively low cost.

The nature of the invention may readily be understood by reference to one embodiment thereof illustrated in the accompanying draw- In said drawing:

Fig. 1 is a longitudinal section through a pipe and an apparatus arranged to form slots therein;

Fig. 2 is a transverse section taken on the plane 22 of Fig. 1;

Fig. 3 is a partial section of the device for controlling the outward travel .of the cutting tools; and

Fig. 4 is a detail section taken on the plane 4-4 of Fig. 3.

To simplify the following description, the expression slot will be employed to include the various types of grooves, perforations or splines embraced within the invention, and the expression pipe will be employed to include tubing and other articles adapted to be slotted or the like.

The invention is here shown applied to the manufacture of well strainers ID. The latter are advantageously provided with elongated slots H which are outwardly tapered so as to be selfcleaning or to prevent clogging. The formation of such outwardly tapered slots has heretofore involved difficulties either in the cost of formation of the slots or in the development of weaknesses in the strainer pipe. In the latter case, the slots are formed by rotary saws (similar to milling cutters) having outwardly tapered contours which result in the formation of excessively elongated internal grooves in the pipe at the ends of the slots. While the slots may be formed rapidly and at relatively low cost by this method, the arrangement of the slots end to end results in the merging of the terminal groove of one slot with that of the next slot, thus forming weakened spots which frequently crack particularly when the strainer is driven into the well or otherwise subjected to the stresses usually imposed upon well strainers.

According to the present invention, it is possible to form, at no less speed and at no greater cost, slots II having no elongated grooves or weak spots at their ends but terminating in relatively blunt extremities I2 having the same taper as the side walls l3 of the slot. As here shown,

the slots are formed by rotating tools or bits l4 having contours l5 corresponding to the desired taper of the walls of the slot. The tips of the bits are advantageously in the form of drills and the conical portions l5 are fluted much as a counter-boring tool. If internal splines or grooves are to be formed, bits having an appropriately shaped contour are employed. After penetrating the pipe the proper distance, the bits are moved in the direction of the desired slot. This may be either transversely, longitudinally or spirally. Generally the arrangement is either longitudinal, as here shown, or spiral. Slots in longitudinal alignment may be placed relatively close together without developing any weak spot in the space l6 between the slots. Preferably adjacent rows of slots are staggered.

The slots may be formed rapidly and cheaply by employing a plurality of bits M- mounted so that they may be simultaneously operated. As here shown, the bits are carried in a head I? in this case arranged with six sets of bearings l8 for mounting six radial bits. Each of the bits is driven by a sleeve l9 within which it is longitudinally slidable. To transmit rotation the bit holders 20 are either splined within the sleeves or, as in the present case, both the holder and the internal bore of the sleeve are made non-circular in section, such for example as hexagonal. The sleeves are each provided with bevel pinions 2| meshing with and driven by a central bevel gear 22 carried on a longitudinally extending spline shaft 23 supported in bearings 24 mounted in a hub projecting from the head ll. Rotation of the shaft 23 thus rotates all of the bits simultaneously.

The bits are moved outwardly in this instance by a conical wedge 25 having a plurality of grooves 26 within which seat the tapered extremities of the rods 21 which are connected to and extend inwardly from the respective bit holders 2!]. The conical wedge 25 is rotatively mounted at the end of a feeding screw 28 threaded into the hub 29 on the head. As shown in Figs. 3 and 4, the wedge member is provided with a key or set screw 30 adapted to project into a groove 3| at the end of the screw and thus maintain an operative connection with the screw without interfering with relative rotation. Rotation of the screw causes advance of the conical wedge relative to the bits, thus causing a radial movement of the latter. As here shown, the bits are held in operative connection with the wedge by springs 32 which are mounted between collars 33 seated against shoulders 34 in the sleeves l9 and collars 35 carried by the rods 21. The screw 28 is provided with an operating connection here shown in the form of a transversely extending pin 36 which may be engaged by an appropriate tool to rotate the screw and move the bits either inwardly or outwardly, as desired.

After'the bits have been driven outwardly, so as to penetrate the pipe by the desired amount (for a groove or spline the pipe will not of course be completely pierced), the head and pipe are moved relatively to form slots. If longitudinal slots be desired, the relative movement is purely longitudinal. If spiral slots be desired, the head and pipe are relatively moved longitudinally and relatively rotated. Upon the completion of a set of slots, the screw 28 is rotated to cause the bits to move inwardly to clear the pipe and thereupon the head is moved relative to the pipe to a position where the next set of slots are to be formed.

The head is here shown mounted on a sleeve 31 screwed in the plate 38 on the head. The sleeve serves not only to support the head but in this instance to effect the aforesaid relative movement between the pipe and head to move the same relative to the pipe. The shaft 23 is advantageously provided with a spline 39 to permit the latter to move longitudinally in its driving member.

Obviously the invention is not limited to the details of the illustrative construction since these may be variously modified. Moreover, it is not indispensable that all features of the invention be used conjointly since various features may be used to advantage in diiferent combinations and subcombinations.

Having described my invention, I claim:

1. Apparatus for slotting pipe or the like comprising in combination a supporting head having a plurality of radial outwardly tapered bits, rotatable sleeves in said head in which said bits are radially slidable, said bits and sleeves being provided with non-circular portions for rotatably connecting the sleeves with the bits, means for sliding said bits in said sleeves, and means for rotating said sleeves.

2. In apparatus for forming outwardlytapering slots with ends having no greater taper than that of the sides of the slots, the combination comprising an operating shaft, a head carried thereby and adapted to extend into the article to be slotted, a rotary drilling bit carried by said head and operatively connected to said shaft, means for axially displacing said bit outwardly to perform a drilling operation, said .bit having tapered cutting edges along its sides for cutting a tapered hole, and means for moving said head and said'bit longitudinally to mill a slot with said tapered cutting edge.

3. In apparatus for cutting slots or the like the combination comprising a head having a plurality of outwardly extending bits each provided with cutting edges along their sides, means for rotating said bits, means for displacing said bits in the'direction of their length to drill holes in the article to be slotted, and means for effecting a relative movement'between the head and the article thereby to cause said bits to mill said holes into slots with said side cutting edges.

4. In apparatus for forming outwardly tapering slots in pipe and the like, the combination comprising a head adapted to extend into'the pipe, a rotary drilling and milling tool carried thereby for cutting a conical hole in the pipe of the same taper as the desired taper of the slot, means for axially displacing said tool outwardly to out said hole, and mechanism for relatively moving the pipe and said head to mill said hole in the direction of the desired slot.

5. In apparatus for forming outwardly tapering slots with ends having no greater taper than that of the sides of the slots, the combination comprising an operating shaft, a head carried by said shaft and adapted to extend into the article to be slotted, a rotary drilling and milling tool carried by said head and operatively connected to said shaft, a wedging means acting against the end of said tool for moving said tool outwardly to perform a drilling operation, said tool having tapered cutting edges along its sides for cutting a tapered hole, and means for moving said head and said tool longitudinally to mill a slot.

EARLE G. BOYERL 

